It was meant to be the next step in airport security, but the trial of face scanning technology at Manchester Airport has run into a whole host of problems.
The main worry is that the scanning machines allow two people in on just one passport with the system.
This flaw was found out when a security guard followed one passenger through and no alarm was sounded.
The security breaches were found by the Daily Telegraph newspaper, which has been speaking to a source in the UK Border Agency (UKBA).
Serious security problem
"This is a massive loophole and a serious problem for security," said the source.
"It should certainly sound an alarm if there are two people trying to come through at the same time. It could lead to widespread immigration abuse and compromise the efficiency of immigration control.
"One particular concern is that it could be exploited by child traffickers, because it won't pick up if you have a child on your back."
Another worry is how regularly the machines break down. The five scanners in Manchester are all linked up, so when one breaks down, it seems that they all do.
The UK Border Agency source continued his rant to the Telegraph, saying: "This is a live trial, and that is dangerous because a six-month trial is long enough for plenty of problems to happen. Only one in 20 of the admissions to the UK through the new machine will be examined by an immigration officer.
"If someone manages to get through without being seen and they are someone an immigration officer has suspicions about, it will be too late. They'll be in Britain."
The face scanners were set up almost two months ago in Manchester. The technology has got the backing from Home Secretary Jacqui Smith who has called for the scanners to be a "ring of security" for the UK and its borders.